function y=Theorem4_2(u,mu,sigma,a,alpha,gamma)
y=(1-(u/a)^(1-2*mu/sigma^2))*(1-2*mu/sigma^2)^2*alpha^(-2*mu/sigma^2)*(1-gamma/a)^(2*mu/sigma^2-2)/(a^(2-2*mu/sigma^2)*(1-(alpha/a)^(1-2*mu/sigma^2)));

